I like the Creative Grid rulers, and I'll tell you why. They have black AND white lines, so you can see on light or dark fabric. And they have dashed lines instead of solid lines. You can see where the edge of the fabric is, in relation to the lines, with a dashed line. They also have the rough dots on the back so they grip better. My 4 favorite sizes are 6 1/2" X 24 1/2", 6 1/2" X 12 1/2", 6 1/2" square and 12 1/2" square. It's important for the squares to have their diagonal line in the very corner of the ruler, so you can square-up your half-square-triangles, etc.